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	<script type="text/javascript">
		var a = "3" == 3;			//"3"==3是true，所以a就是true
		var b = "4" === 4;			//"4"===4是false,所以b就是false
		console.log(a || b);		//true || false  , 结果是true
		console.log(a && b);		//true && false   , 结果是false
		console.log(a && !b);		//true && !false  , 结果是true
		console.log(!a && b); 		//!true && false   , 结果是false
	</script>
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